using System;
using System.Collections.Generic;
using System.IO;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.Json.Serialization;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Data.Sqlite;

namespace AISApp
{
    // JSON DTOs for API
    public sealed class ChatMessage
    {
        [JsonPropertyName("role")] public string Role { get; set; } = "";
        [JsonPropertyName("content")] public string Content { get; set; } = "";
    }

    public sealed class ChatRequest
    {
        [JsonPropertyName("model")] public string Model { get; set; } = "";
        [JsonPropertyName("messages")] public List<ChatMessage> Messages { get; set; } = new();
        [JsonPropertyName("temperature")] public double Temperature { get; set; } = 0.0;
    }

    public sealed class ChatChoice
    {
        [JsonPropertyName("message")] public ChatMessage Message { get; set; } = new();
    }

    public sealed class ChatResponse
    {
        [JsonPropertyName("choices")] public List<ChatChoice> Choices { get; set; } = new();
    }

    public sealed class AIS
    {
        // -------- Static / constants --------
        private static readonly HttpClient Http = new HttpClient();
        private static readonly JsonSerializerOptions JsonOpts = new JsonSerializerOptions
        {
            PropertyNameCaseInsensitive = true,
            WriteIndented = false
        };

        public static readonly Dictionary<string, string> PredefinedModels = new(StringComparer.OrdinalIgnoreCase)
        {
            ["dobby"]        = "sentientagi/dobby-mini-unhinged-plus-llama-3.1-8b",
            ["dolphin"]      = "cognitivecomputations/dolphin-mixtral-8x22b",
            ["dolphin_free"] = "cognitivecomputations/dolphin3.0-mistral-24b:free",
            ["gemma"]        = "google/gemma-3-12b-it",
            ["gpt-4o-mini"]  = "openai/gpt-4o-mini",
            ["gpt-4.1-nano"] = "openai/gpt-4.1-nano",
            ["qwen"]         = "qwen/qwen3-30b-a3b",
            ["unslop"]       = "thedrummer/unslopnemo-12b",
            ["euryale"]      = "sao10k/l3.3-euryale-70b",
            ["wizard"]       = "microsoft/wizardlm-2-8x22b",
            ["deepseek"]     = "deepseek/deepseek-chat-v3-0324"
        };

        // -------- Instance state (mirrors Python) --------
        public string Name { get; private set; }
        public double Temperature { get; private set; }
        public double Backoff { get; private set; }
        public int MaxRetries { get; private set; }
        public bool SafeMode { get; private set; }
        public string SystemMessage { get; private set; }
        public string Model { get; private set; }
        public string BaseUrl { get; private set; }
        public string Rel { get; private set; }
        public string ApiKey { get; private set; }
        public string DbName { get; private set; }
        public bool Loaded { get; private set; }

        private readonly List<ChatMessage> _messages = new();
        private readonly SqliteConnection _conn;

        private Dictionary<string, string> Headers => new()
        {
            ["Authorization"] = $"Bearer {ApiKey}",
            ["Content-Type"]  = "application/json"
        };

        // -------- ctor --------
        public AIS(
            string? systemMessage = null,
            string model = "gemma",
            int maxRetries = 3,
            double backoff = 1,
            string? name = null,
            double temperature = 0.0,
            string dbName = ":memory:",
            bool safeMode = true,
            string baseUrl = "openrouter.ai",
            string rel = "/api",
            string? apiKey = null
        )
        {
            Loaded = dbName != ":memory:" && File.Exists(dbName);
            DbName = dbName;

            // Open connection and create schema
            _conn = OpenConnection(dbName);
            InitDb();

            // If existing DB, hydrate settings first
            if (Loaded)
            {
                temperature = GetSetting("temperature", temperature);
                name        = GetSetting("name", name ?? "");
                backoff     = GetSetting("backoff", backoff);
                maxRetries  = GetSetting("max_retries", maxRetries);
                safeMode    = GetSetting("safe_mode", safeMode);
                systemMessage = GetSetting("system_message", systemMessage ?? "");
                model       = GetSetting("model", model);
            }

            if (string.IsNullOrEmpty(systemMessage))
            {
                systemMessage = "You respond like a calculator; only the result is the answer. Respond only with the result. No explanations or extra words.";
            }

            SystemMessage = systemMessage;
            Name = !string.IsNullOrEmpty(name)
                ? $"ais_{name}"
                : $"ais_{Guid.NewGuid().ToString("N").Substring(0, 8)}";

            Backoff      = backoff;
            SafeMode     = safeMode;
            MaxRetries   = maxRetries;
            BaseUrl      = baseUrl;
            Rel          = rel;
            ApiKey       = apiKey ?? Environment.GetEnvironmentVariable("OPENROUTER_API_KEY")
                           ?? "sk-or-REPLACE_ME"; // keep explicit default like Python had
            Temperature  = temperature;
            Model        = PredefinedModels.TryGetValue(model, out var mapped) ? mapped : model;

            if (MessagesExist())
            {
                _messages = LoadMessages();
            }
            else
            {
                _messages.Add(new ChatMessage { Role = "system", Content = SystemMessage });
                SaveMessage("system", SystemMessage);
            }

            Console.WriteLine($"[INFO] Initialized AIS name={Name} model={Model} db={DbName}");
        }

        // -------- DB helpers --------
        private static SqliteConnection OpenConnection(string dbName)
        {
            var cs = dbName == ":memory:" ? "Data Source=:memory:" : $"Data Source={dbName}";
            var conn = new SqliteConnection(cs);
            conn.Open();
            return conn;
        }

        private void InitDb()
        {
            using var cmd1 = _conn.CreateCommand();
            cmd1.CommandText = @"
                CREATE TABLE IF NOT EXISTS messages (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    role TEXT NOT NULL,
                    content TEXT NOT NULL
                )";
            cmd1.ExecuteNonQuery();

            using var cmd2 = _conn.CreateCommand();
            cmd2.CommandText = @"
                CREATE TABLE IF NOT EXISTS settings (
                    id INTEGER PRIMARY KEY AUTOINCREMENT,
                    name TEXT NOT NULL,
                    json_value TEXT NOT NULL
                )";
            cmd2.ExecuteNonQuery();
        }

        private bool MessagesExist()
        {
            using var cmd = _conn.CreateCommand();
            cmd.CommandText = "SELECT COUNT(*) FROM messages";
            var count = Convert.ToInt32(cmd.ExecuteScalar());
            return count > 0;
        }

        private List<ChatMessage> LoadMessages()
        {
            var list = new List<ChatMessage>();
            using var cmd = _conn.CreateCommand();
            cmd.CommandText = "SELECT role, content FROM messages ORDER BY id ASC";
            using var rdr = cmd.ExecuteReader();
            while (rdr.Read())
            {
                list.Add(new ChatMessage
                {
                    Role = rdr.GetString(0),
                    Content = rdr.GetString(1)
                });
            }
            return list;
        }

        private void SaveMessage(string role, string content)
        {
            using var cmd = _conn.CreateCommand();
            cmd.CommandText = "INSERT INTO messages (role, content) VALUES ($r, $c)";
            cmd.Parameters.AddWithValue("$r", role);
            cmd.Parameters.AddWithValue("$c", content);
            cmd.ExecuteNonQuery();
        }

        // Generic typed setting helpers
        private T GetSetting<T>(string name, T defaultValue)
        {
            using var cmd = _conn.CreateCommand();
            cmd.CommandText = "SELECT json_value FROM settings WHERE name = $n LIMIT 1";
            cmd.Parameters.AddWithValue("$n", name);
            var obj = cmd.ExecuteScalar();
            if (obj is string s)
            {
                try
                {
                    var node = JsonNode.Parse(s);
                    if (node is null) return defaultValue!;
                    return node.Deserialize<T>(JsonOpts)!;
                }
                catch
                {
                    return defaultValue!;
                }
            }
            return defaultValue!;
        }

        private void SetSetting(string name, object? value)
        {
            var json = JsonSerializer.Serialize(value, JsonOpts);

            using (var upd = _conn.CreateCommand())
            {
                upd.CommandText = "UPDATE settings SET json_value = $v WHERE name = $n";
                upd.Parameters.AddWithValue("$v", json);
                upd.Parameters.AddWithValue("$n", name);
                var rows = upd.ExecuteNonQuery();
                if (rows == 0)
                {
                    using var ins = _conn.CreateCommand();
                    ins.CommandText = "INSERT INTO settings (name, json_value) VALUES ($n, $v)";
                    ins.Parameters.AddWithValue("$n", name);
                    ins.Parameters.AddWithValue("$v", json);
                    ins.ExecuteNonQuery();
                }
            }

            // Reflectively update instance if property exists (case-insensitive)
            var prop = GetType().GetProperty(name, System.Reflection.BindingFlags.Instance |
                                                   System.Reflection.BindingFlags.Public |
                                                   System.Reflection.BindingFlags.IgnoreCase);
            if (prop != null && prop.CanWrite)
            {
                try
                {
                    var targetVal = value;
                    if (value is JsonNode node)
                    {
                        targetVal = node.Deserialize(prop.PropertyType, JsonOpts);
                    }
                    else if (value is string str && prop.PropertyType != typeof(string))
                    {
                        try
                        {
                            var jn = JsonNode.Parse(str);
                            if (jn != null) targetVal = jn.Deserialize(prop.PropertyType, JsonOpts);
                        }
                        catch { /* ignore */ }
                    }
                    prop.SetValue(this, ConvertIfNeeded(targetVal, prop.PropertyType));
                }
                catch { /* ignore */ }
            }
        }

        private static object? ConvertIfNeeded(object? value, Type targetType)
        {
            if (value == null) return null;
            if (targetType.IsAssignableFrom(value.GetType())) return value;
            try { return Convert.ChangeType(value, targetType); }
            catch { return value; }
        }

        private void SaveSettings()
        {
            SetSetting("name", Name);
            SetSetting("temperature", Temperature);
            SetSetting("backoff", Backoff);
            SetSetting("max_retries", MaxRetries);
            SetSetting("safe_mode", SafeMode);
            SetSetting("system_message", SystemMessage);
            SetSetting("model", Model);
        }

        // -------- Public API (mirrors Python) --------
        public void Append(string messageUser, string messageAssistant, bool save = true)
        {
            _messages.Add(new ChatMessage { Role = "user", Content = messageUser });
            if (save) SaveMessage("user", messageUser);
            _messages.Add(new ChatMessage { Role = "assistant", Content = messageAssistant });
            if (save) SaveMessage("assistant", messageAssistant);
        }

        public void Save(string dbPath)
        {
            if (DbName != ":memory:")
            {
                Console.WriteLine("[INFO] Already using persistent database.");
                return;
            }
            var dbFile = dbPath.EndsWith(".db", StringComparison.OrdinalIgnoreCase) ? dbPath : dbPath + ".db";

            using var dest = new SqliteConnection($"Data Source={dbFile}");
            dest.Open();
            _conn.BackupDatabase(dest);
            dest.Close();

            DbName = dbFile;
            Console.WriteLine($"[INFO] Converted in-memory DB to persistent DB at {DbName}");
        }

        public void PatchTime()
        {
            const string timePrefix = "Current time: `";
            if (_messages.Count == 0) return;

            var content = _messages[0].Content ?? "";
            var nowStr = DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss");

            if (content.StartsWith(timePrefix, StringComparison.Ordinal))
            {
                var end = content.IndexOf('`', timePrefix.Length);
                if (end >= 0)
                {
                    var rest = content.Substring(end + 1).TrimStart('\n');
                    _messages[0].Content = $"{timePrefix}{nowStr}`\n\n{rest}";
                }
                else
                {
                    _messages[0].Content = $"{timePrefix}{nowStr}`\n\n{content}";
                }
            }
            else
            {
                _messages[0].Content = $"{timePrefix}{nowStr}`\n\n{content}";
            }

            // Persist system message update
            using var cmd = _conn.CreateCommand();
            cmd.CommandText = "UPDATE messages SET content = $c WHERE id = (SELECT MIN(id) FROM messages)";
            cmd.Parameters.AddWithValue("$c", _messages[0].Content);
            cmd.ExecuteNonQuery();
        }

        public async Task<object> ChatAsync(string message, double? temperature = null, CancellationToken ct = default)
        {
            if (!SafeMode)
            {
                // command handling
                if (message.StartsWith("!reset", StringComparison.OrdinalIgnoreCase)) { Reset(); return "true"; }
                if (message.StartsWith("!instruct", StringComparison.OrdinalIgnoreCase)) { Instruct(message.Length >= 10 ? message[10..] : ""); return "true"; }
                if (message.StartsWith("!undo", StringComparison.OrdinalIgnoreCase)) { return Undo().ToString().ToLowerInvariant(); }
                if (message.StartsWith("!get", StringComparison.OrdinalIgnoreCase)) { var key = message[4..].Trim(); return GetRawSettingOr("not found", key); }
                if (message.StartsWith("!set", StringComparison.OrdinalIgnoreCase))
                {
                    var rest = message.Length >= 5 ? message[5..] : "";
                    var idx = rest.IndexOf(' ');
                    if (idx > 0)
                    {
                        var nm = rest[..idx].Trim();
                        var val = rest[(idx + 1)..].Trim();
                        SetSetting(nm, TryJson(val));
                        return "true";
                    }
                }
                if (message.StartsWith("!query", StringComparison.OrdinalIgnoreCase)) { return Query(message.Length >= 6 ? message[6..] : ""); }
                if (message.StartsWith("!edit", StringComparison.OrdinalIgnoreCase)) { Edit(message.Length >= 5 ? message[5..] : ""); return SystemMessage; }
                if (message.StartsWith("!append", StringComparison.OrdinalIgnoreCase))
                {
                    var rest = message.Length >= 7 ? message[7..] : "";
                    var firstColon = rest.IndexOf(':');
                    if (firstColon >= 0 && rest.IndexOf(':', firstColon + 1) < 0)
                    {
                        var user = rest[..firstColon];
                        var assistant = rest[(firstColon + 1)..];
                        Append(user, assistant);
                        return "true";
                    }
                }
            }

            PatchTime();

            _messages.Add(new ChatMessage { Role = "user", Content = message });
            SaveMessage("user", message);

            var payload = new ChatRequest
            {
                Model = Model,
                Messages = _messages,
                Temperature = temperature ?? Temperature
            };

            var json = JsonSerializer.Serialize(payload, JsonOpts);
            var url = $"https://{BaseUrl}{Rel}/v1/chat/completions";
            Console.WriteLine(url);

            int attempt = 0;
            string assistant = "ERROR";
            double backoff = Backoff;

            while (attempt < MaxRetries)
            {
                try
                {
                    using var req = new HttpRequestMessage(HttpMethod.Post, url)
                    {
                        Content = new StringContent(json, Encoding.UTF8, "application/json")
                    };
                    foreach (var kv in Headers) req.Headers.TryAddWithoutValidation(kv.Key, kv.Value);

                    using var resp = await Http.SendAsync(req, ct);
                    var text = await resp.Content.ReadAsStringAsync(ct);

                    var parsed = JsonSerializer.Deserialize<ChatResponse>(text, JsonOpts);
                    assistant = parsed?.Choices?[0]?.Message?.Content ?? "ERROR";

                    SaveSettings();

                    _messages.Add(new ChatMessage { Role = "assistant", Content = assistant });
                    SaveMessage("assistant", assistant);

                    return TryJson(assistant);
                }
                catch (Exception ex)
                {
                    attempt++;
                    Console.WriteLine($"[WARN] Chat attempt {attempt} failed: {ex.Message}");
                    if (attempt < MaxRetries)
                    {
                        await Task.Delay(TimeSpan.FromSeconds(backoff), ct);
                        backoff *= 2;
                    }
                    else
                    {
                        _messages.Add(new ChatMessage { Role = "assistant", Content = "ERROR" });
                        SaveMessage("assistant", "ERROR");
                        Console.WriteLine($"[CRITICAL] Failed after {MaxRetries} attempts.");
                        return "ERROR";
                    }
                }
            }

            return "ERROR";
        }

        public object Chat(string message, double? temperature = null)
            => ChatAsync(message, temperature).GetAwaiter().GetResult();

        // JSON helper that mirrors Python _try_json (also strips ``` fences)
        private static object TryJson(string response)
        {
            var fixedStr = (response ?? "").Trim();
            if (fixedStr.StartsWith("```", StringComparison.Ordinal) && fixedStr.EndsWith("```", StringComparison.Ordinal))
            {
                var lines = fixedStr.Split('\n');
                if (lines.Length >= 2)
                {
                    fixedStr = string.Join("\n", lines, 1, lines.Length - 2).Trim();
                }
            }

            try
            {
                var node = JsonNode.Parse(fixedStr);
                return node ?? response;
            }
            catch
            {
                return response;
            }
        }

        private object GetRawSettingOr(string fallback, string key)
        {
            using var cmd = _conn.CreateCommand();
            cmd.CommandText = "SELECT json_value FROM settings WHERE name = $n LIMIT 1";
            cmd.Parameters.AddWithValue("$n", key);
            var obj = cmd.ExecuteScalar();
            return obj is string s ? s : fallback;
        }

        public void Reset()
        {
            Console.WriteLine("[INFO] Reset conversation history (keeping system message).");
            ChatMessage sys = _messages.Count > 0 ? _messages[0] : new ChatMessage { Role = "system", Content = "" };
            _messages.Clear();
            _messages.Add(sys);

            using var cmd = _conn.CreateCommand();
            cmd.CommandText = "DELETE FROM messages WHERE id != (SELECT MIN(id) FROM messages)";
            cmd.ExecuteNonQuery();
        }

        public void Instruct(string instructions)
        {
            SystemMessage = instructions;
            Console.WriteLine($"[INFO] System instructions updated.");
            SaveSettings();

            if (_messages.Count > 0)
            {
                _messages[0].Content = instructions;
                using var cmd = _conn.CreateCommand();
                cmd.CommandText = "UPDATE messages SET content = $c WHERE id = (SELECT MIN(id) FROM messages)";
                cmd.Parameters.AddWithValue("$c", instructions);
                cmd.ExecuteNonQuery();
            }
            else
            {
                _messages.Add(new ChatMessage { Role = "system", Content = instructions });
                SaveMessage("system", instructions);
            }
            Reset();
        }

        public object Query(string query)
        {
            var response = Chat(query);
            Undo();
            return response;
        }

        private bool DeleteLastMessage()
        {
            try
            {
                if (_messages.Count == 0) return false;
                _messages.RemoveAt(_messages.Count - 1);

                using var cmd = _conn.CreateCommand();
                cmd.CommandText = "DELETE FROM messages WHERE id = (SELECT MAX(id) FROM messages)";
                cmd.ExecuteNonQuery();
                return true;
            }
            catch (Exception e)
            {
                Console.WriteLine($"[ERROR] Undo error: {e.Message}");
                return false;
            }
        }

        public bool Edit(string change)
        {
            var prompt = $"Apply this update: `{change}` to `{SystemMessage}` and return the result";
            var result = Query(prompt);
            var newSys = result is JsonNode jn ? jn.ToJsonString() : result?.ToString() ?? SystemMessage;
            Instruct(newSys);
            return true;
        }

        public bool Undo()
        {
            // delete assistant + user
            return DeleteLastMessage() && DeleteLastMessage();
        }

        public void Repl()
        {
            Console.WriteLine("[INFO] REPL started. Ctrl+C to quit.");
            while (true)
            {
                try
                {
                    Console.Write("You: ");
                    var line = Console.ReadLine();
                    if (string.IsNullOrWhiteSpace(line)) continue;

                    var response = Chat(line);
                    var typeName = response switch
                    {
                        JsonNode => "JsonNode",
                        null => "null",
                        _ => response.GetType().Name
                    };
                    Console.WriteLine($"{Name}: {typeName} {FormatForPrint(response)}");
                }
                catch (OperationCanceledException) { break; }
                catch (Exception ex)
                {
                    Console.WriteLine($"[CRITICAL] Unexpected error: {ex.Message}");
                    Console.WriteLine("AI: ERROR");
                }
            }
        }

        private static string FormatForPrint(object? obj)
        {
            if (obj is JsonNode jn) return jn.ToJsonString(new JsonSerializerOptions { WriteIndented = false });
            return obj?.ToString() ?? "null";
        }
    }

    internal static class Program
    {
        // Equivalent to: if __name__ == '__main__': ai = AIS(model="wizard", safe_mode=False); ai.repl()
        private static void Main(string[] args)
        {
            var ai = new AIS(model: "wizard", safeMode: false);
            ai.Repl();
        }
    }
}